Joker: Folie à Deux' actor Harry Lawtey told 'Variety' that he and Joaquin Phoenix pranked Lawtey's mother by having Phoenix appear on their FaceTime call while wearing his full Joker makeup. "I said,

Lawtey didn’t just walk away with a funny story either, he also gained invaluable experience working alongside Joaquin, who The Pale Blue Eye star describes as someone who delivered “a master class” every day on set. According to Harry, the Gladiator veteran actor's commitment to the role left a lasting impression on him.

Christian Bale's voice as Batman in the "Dark Knight" trilogy is infamous - and infamously bad for the vocal cords - but as it turns out, Joaquin Phoenix's unhinged laugh as Arthur Fleck in the "Joker" films was also a bit of a health hazard.

Folie à Deux, recalled the time he and Joaquin Phoenix played a trick on Lawtey’s mom on the movie set. Phoenix stayed in full Joker makeup on set, even when not filming, so Lawtey said the actor played a trick on his unsuspecting mom.